Various devices are known in the art for delivering heavy viscous materials, for example, grease caukling compound, printing ink and the like to a desired end point of use. It is also known to employ air pressurized cylinders to operate grease guns, caulking guns, pastry dough feeders and automatic machine lubrication systems. In the tobacco industry it is conventional to employ printing units for various purposes, among others, the printing of brand names on cigarette wrappers. It has been conventional in such cigarette manufacturing printing operations to supply ink to the printing unit from a supply cartridge or reservoir mounted on the printing unit. Such known arrangement has a number of drawbacks. For one thing, the cartridge has a limited capacity, being suited for use during only about one shift operation, i.e., for holding about eight hours of ink supply before the cartridge must be refilled. If only a single cartridge is used on the printing unit, it must temporarily be taken out of service to permit the cleaning of the cartridge and refilling of the same with a quantity of ink before it can be returned to the manufacturing line. If a plural supply cartridge system is employed, so that downtime or removal of the printing unit from the manufacturing line is not necessary, there still remains the task of cleaning an empty catridge and refilling of the same before it is available for further and future use. Further problems attending the use of known printing units employing reservoir or cartridge-type ink-holding means is caused by the entrapment of air in the ink mass during the refilling of the cartridge. Since the supply from the cartridge to the printing unit is in a closed system, ultimately such air will exit the system at the printing unit leading to the possibility of failure to print on cigarette wrappers during the time it takes for the air to escape from the printing unit. Since the ink used in the operation is a relatively thick material of grease-like consistency, it is difficult for the air to be removed by any other means than by expulsion through the printing unit.
Accordingly, it is desirable that a more effective, efficient and economical means of supplying printing ink to a printing unit in a cigarette manufacturing process line be provided.